A large number of genetic diseases occur in dogs mainly due to founder effects and population bottlenecks resulting from centuries-old inbreeding practices. These include von Willebrand disease, severe combined immunodeficiency disorder, X-linked Duchenne type muscular dystrophy, pyruvate kinase deficiency, muscle type phosphofructokinase deficiency, hemophilia and narcolepsy. More than fifty-eight percent of dog genetic diseases, such as Duchenne-type muscular dystrophy, are true homologues of human diseases caused by mutations in the same gene. In addition, many of the more than 400 modern dog breeds show a high prevalence of more complex multigenic diseases, including allergies, cancers, blindness, heart disease, cataracts, epilepsy, hip dysplasia and deafness. Because of obvious parameters such as lifespan and size, dogs represent an important model for human disease. In dogs, the physiology, disease presentation and clinical response often parallels that of the human more closely than the corresponding mouse model. They therefore provide a unique preclinical model to test the usefulness of regenerative medicine and tissue engineering approaches to the treatment and cure of Human disease. Pivotal to these new approaches will be the use of the differentiated derivatives of embryonic stem cells (ES). The recent demonstration that is possible to generate autologous, pluripotent stem cells (iPS) from skin fibroblasts, by relatively simple reprogramming steps is a major scientific advance which will have profound ramifications in many areas of basic research and applied clinical medicine. It is our central hypothesis that the generation and characterization f canine iPS cell lines will hasten the development of replacement tissues and organs in human. In order to address this hypothesis the following three specific aims are proposed (1) To generate induced pluripotent stem cell lines (iPS) from normal and dystrophic (GRMD) dogs. (2) Gene expression profiles of iPS lines will be characterized and compared to a blastocyst derived canine (3) To assess the pluripotency of canine ES and iPS lines in vivo and in vitro.